There is a lot of (mis)information floating around the web about what’s
important when shopping for a mouse. The goal of this page is to give you an
intuitive understanding of the various factors regarding mice.

How much will a mouse cost me?

Good mice don’t have to cost an arm and a dick, what I consider to be the
perfect gaming mouse at the moment only costs $25 on amazon - the
Nixeus Revel. Don’t believe the marketing on these $200
mice, use the information on this page to make an informed purchase.

Sensor

Resolution / CPI / DPI / PPI

First of all, just to clarify:

DPI (Dots Per Inch): A term used in the printer world to describe how many
little blobs of color (dots) the printer can fit in a linear inch

PPI (Pixels Per Inch / Pulses Per Inch):

Pixels Per Inch: A term used in the display world to
describe the pixel density, also measured in linear inches

Pulses Per Inch: What people called CPI long ago

CPI (Counts Per Inch): This is the correct term for mice, like with all the
other “per inch” measurements, this is measured in linear inches

There are a few ways to think about CPI, if you google it you’ll get something
along the lines of “the number of steps the sensor will report after moving one
linear inch”. I think a more intuitive way to think about it is by looking at
the extremes. If we have a mouse with 1 CPI that means we will have to move the
mouse an entire inch before a single movement step is sent to the computer.

In other words, CPI is the measure of the minimum physical movement of the mouse
which will be sent to the computer. You can test this yourself by plugging in a
mouse that can be set to 100 CPI (or lower) and very gently moving it. You will
notice the discrete steps the cursor takes. A higher CPI means a more accurate
representation of the movement will be reported to the computer.

There are two caveats with resolution:

At some point the movement reported by the mouse will be smaller than the
minimum visually noticeable movement on your monitor / in your game. At this
point raising the CPI will not produce visual differences. This number depends
on your resolution, and your field of view.

Some mouse manufacturers will use the microcontroller to fudge the numbers
that the sensor can actually achieve, check the sensor specifications and make
sure it lines up with what the mouse claims. If this is the case, it is likely
the mouse will have jitter

A rough estimate for the maximum useful CPI is to look at this extreme example:
4k (aka 2160p) resolution width is 3840 pixels, combine this with a 3D game
which defaults you to 60 degrees field of view (borderlands 1?) and you get a
total of 3840 * (360⁄60) = 23040 pixels per 360 degree rotation. If you have a
very high sensitivity of 4 inches per 360 degree rotation that gives us a
maximum useful CPI of 23040 / 4 = 5760 CPI.

Generally speaking, anything above that will not provide a benefit to you.
I’ve put those numbers from the example above into this little calculator, give
it a shot to see what the maximum useful CPI is for you personally:

Polling Rate / Refresh Rate / Hertz (Hz)

This section is about the USB polling rate, not the sensor refresh rate. I have
yet to see a sensor which has a refresh rate slower than the USB polling rate.
This is only part of the sensor section because it’s often associated with the
sensor.

The polling rate is the rate at which your computer asks your mouse to send an
update. I am not a fan of this definition because it doesn’t give you an
intuitive concept around the consequences of low polling rates, for that we’ll
conduct a little thought experiment in the next paragraph. An easy way to
think about the polling rate is by looking at it as the maximum variance in
response time. In other words a 125Hz polling rate has a maximum variance of
8ms - This means you will see your cursor respond anywhere between ~0ms and 8ms
after the physical movement of the mouse.

We will start our thought experiment with two identical mice with differing
polling rates: a 1Hz mouse, and a 1000Hz mouse. If we move both mice one inch on
the mouse pad, will they move the same distance on the screen? Yes, they will -
even though one is polled once per millisecond and the other is polled once per
second, the total distance reported by the mouse will be the same. The real
question is: How long will it take for the 1Hz mouse to complete the motion?

The answer is very interesting: it’s possible that the 1Hz mouse actually
ends up moving the cursor the total distance more quickly than the 1000Hz
mouse. How is that possible? If the 1Hz mouse sends an update and then 999.5
milliseconds later you move the mouse 1 inch another update will be sent only
half a millisecond later, whereas if the 1000Hz mouse sends an update then
immediately after you move the mouse 1 inch another update will be sent one
whole millisecond later. In that exact scenario the 1000Hz mouse is slower
to respond than the 1Hz mouse. However, the variance on the 1Hz mouse is
extremely high, your response time could be anywhere in the range of ~0ms to
1000ms after the physical movement of the mouse. The 1000Hz mouse will respond
anywhere between ~0ms and 1ms after the physical movement of the mouse.

This example is ridiculous, but it helps you understand an important consequence
of polling rates: The higher the polling rate, the lower the variance of the
response time, and therefore the higher the predictability.

One very interesting subtlety of mouse polling rates has to do with monitor
refresh rates. If you have a 60Hz monitor and a 125Hz mouse then the best case
visual response time is still ~0ms, if the monitor and your mouse refresh
virtually at the same time you physically move the mouse. In the worst case you
move the mouse right after a mouse refresh, which then takes 8ms for the next
refresh. The monitor then refreshes just before the mouse information is
processed so you have to wait an additional 17ms for the monitor to refresh, and
finally after 25ms you see the cursor move. So the variance of this setup is
between 0 and 25ms. The visual variance of a 144Hz monitor and a 1000Hz mouse is
between ~0ms and 8ms.

The key to consistency is predictability, you want to minimize the variance of
your setup in order to perform more consistently. Since this isn’t a guide to
buying a monitor I will give recommendations for the mouse sensor only: The
higher the polling rate, the better, period.

Some nerds might give some crappy arguments like:

To that I say: Show me a computer that will run your FPS game but struggle
handling 1KHz polling rate. The human eye arguments really annoy me because
they’re just completely wrong. First of all, you can easily disprove this
by comparing a 60Hz monitor and a 120Hz monitor, everyone can see the difference
just by spinning the mouse cursor in a circle. Second of all, when you play at a
very high level your hands will move faster than you can decipher the visual
information. If you’re not convinced, set your monitor’s max refresh rate to
30Hz and downclock your mouse to 30Hz… GOOD LUCK!

Acceleration

The acceleration of a mouse sensor is usually rated in g’s, this rating
represents the maximum linear acceleration the sensor can undergo and still
function accurately.

I used an NGIMU to measure the linear acceleration
that I could apply with my arm. I went through some regular motions and then
some more vigorous movement; You can see the data in the following video:

In this video I was able to reach an acceleration just shy of 13g. After the
video I tried holding the sensor in my hand and moving as fast as I possibly
could and was actually able to max out my NGIMU at 16g. I don’t think I was
moving much faster than 16g though. This data shows that if you want a
sensor which won’t get in your way with “twitchy” movements (like clearing long
doors on dust2 coming from ct side) you need a sensor rated for at least 13g
of acceleration - to be safe get one with 20g or more since that seems to be the
limit of what a human shoulder can produce.

Tracking Speed / Inches Per Second (IPS)

Tracking speed is most often rated in inches per second. It’s the maximum
linear velocity which the sensor will accurately record.

I tested how fast I could move my mouse 18 inches and measured the time it took.
The fastest time I was able to perform was 0.13 seconds - measured on my phone’s
stopwatch. Those numbers give me an average velocity of about 138 inches per
second. I moved at a similar velocity as my 13g measurements in the video
testing acceleration. My recommendation is to look for sensors rated a little
bit higher than that to account for some error in my measurements and also
differences in our anatomy.

Lift Off Distance (LOD)

There’s not much to say here, every sensor has a working distance. If you play
on low sensitivity or for some other reason find yourself lifting the mouse off
of the surface often, then you want a lower lift off distance. I personally play
on a very low sensitivity so I look for a lift off distance of less than 3mm.
Some sensors have configurable lift off distances. Every mouse will seat the
sensor slightly differently so this is more of a mouse specific measurement
rather than a sensor measurement.

There is a trick you can do by taping the sensor aperture
which will lower the lift off distance at the expense of other mouse specs. I
recommend using this as a last resort, instead look for a mouse with the right
lift off distance for you.

Optical vs Laser

The only reason this should influence your decision is due to which surfaces
these mice work on. An optical mouse works by shining visible or IR light to
illuminate the surface, as you can expect it struggles with reflective, and
translucent surfaces. Laser mice generally use light as well, but in a laser to
illuminate the surface and generally perform much better on reflective and
translucent surfaces. There are different laser technologies though, even within
the “laser” category you will find some work better than others on some
particular surfaces (like mirrors or whatever kids are using for mousepads these
days). I haven’t seen a sensor that doesn’t work on a cloth mat.

Flaws & Flawless Sensors

Some sensors, or sensor firmware, or microcontrollers introduce “flaws” into the
output of the mouse. If there is any distortion of the signal that the sensor or
microcontroller receives and it cannot be disabled, then it is a flaw. You want
to look for a sensor which has none of the following issues:

Pointer Acceleration / Tracking Speed Inconsistency

Not to be confused with the sensors rated acceleration, this has to do with the
output of the mouse. If your mouse has pointer acceleration then the distance
pointer moves on the screen is a function of both the physical travel of the
mouse and the velocity which the distance was travelled. Some people add pointer
acceleration through software, which is perfectly fine - but you absolutely do
not want it built into the hardware you purchase. Pointer acceleration will make
it harder to develop muscle memory.

Axis Asymmetry

Some sensors have differing sensitivities (maybe due to CPI distribution?) on
different axes. A mouse should work the same regardless of the axis it’s moved.

Prediction / Drift Correction / Angle Snapping

Some mice will try to correct your nearly horizontal or vertical movements and
report them to the computer as true horizontal or vertical movement. In other
words if the mouse thinks that you are trying to move in a straight line it will
kindly tell the computer you’re moving in a straight line. Some people like this
feature, most people do not.

Jitter

Some mice use either extrapolation or other techniques to claim higher CPI
numbers than the sensor is actually capable of. Often this causes the movement
to feel as if they’re moving a little bit too far, or a little bit in the wrong
direction.

Feet / Skates

Most people want feet with the lowest amount of friction to the mousepad.
Generally speaking PTFE (also known colloquially as TeflonTM) is a
good choice for mouse foot material since it has an incredibly low coefficient
of friction.

There are some people who prefer more friction, if you are one of those people I
recommend looking into “control” mousepads. Usually they are metal with a coarse
surface. If you use one of these pads your feet will wear down more quickly.

When looking at mouse feet, one thing we should note is that friction is
independent of surface area. So in the friction case size does not matter.
However in the case of wear - the larger the mouse foot, the longer it will
take to wear down. Many mouse manufacturers will sell you replacement feet,
there even exists a 3rd party market for feet (see
Hyperglide).

If there is a mouse which is perfect for you but uses a crappy material for the
feet or the feet have worn out and you can’t find replacements, you can purchase
a roll of PTFE adhesive tape (solid not woven). This tape is basically
a very thin amount of PTFE which you stick right on top of your mouse feet and
use a razor blade to cut it down to size. This will perform just as well as
solid PTFE feet, but will wear down quickly depending on the material your mouse
pad is made of.

Switches

Mouse Buttons

Many of you may already be familiar with the concept of switches from your fancy
mechanical keyboards, well it’s the exact same for mice. There are different
manufacturers for the switches, however, it isn’t a very hot topic of debate.
Cherry of the mechanical
keyboard world is analogous to Omron in the mouse world.
Omron makes two types of switches, one with a 0.6 newton actuation force, and one with
a 1.2 newton actuation force. If the sensitivity of the mouse switch is important
to you then you should pay attention to which switch your prospective mouse has.
You can differentiate these by the color of the plunger
on the switch itself.

Scroll Wheel

The scroll wheel is technically also a switch. To my knowledge there is no Omron
or Cherry of the scroll wheel world - although many swear by Logitech’s
“infinite” scroll wheels.

Shape & Weight

Claw Grip - The base of the palm and the finger tips lay on the mouse surface

Fingertip Grip - Only the fingertips lay on the mouse surface

My personal recommendation is to measure from the middle of your palm to the tip
of the longest finger. For palm grip the mouse should be at least that long. For
claw grip it should be at least one inch shorter than that. For fingertip grip
it doesn’t matter what the length is. The shape of the mouse can play some role
in the sizing too so check the reviews on the particular mouse you’re looking at
if you think it might be an issue.

The weight of the mouse is a debated topic. Some companies market heavy mice,
some market light mice, and some market adjustable weight mice. The physical
consequences of a heavy mouse are: more friction, slower acceleration of mouse.
Some people argue that this gives you a more accurate mouse movement… I don’t
buy it. I think a heavier mouse actually makes you less accurate in the same way
a dull knife makes you less precise. The less effort it takes to make the
movement, the more you can focus on the quality of the motion. There is a very
small difference in weight between the heaviest and lightest mice, so it likely
makes a very small difference in performance - pick what’s more comfortable.

If you’re having wrist problems and want a mouse that will help you prevent
further injury then I highly recommend a vertical mouse. Unfortunately there
aren’t any performance vertical mice on the market - all the sensors in use are
garbage. The best one I found in my years of gaming with a vertical mouse was
the Delux M618LU. There are many versions of this mouse,
but this particular one uses a decent sensor, I’m not sure what it is but it has
a medium acceleration (around 10g). If you’re looking to game on a vertical
mouse that’s what you need. The best thing you can do for your wrists is
strengthen them, handstands and ring holds will give you iron wrists. I
recommend that method over any vertical mouse.

Memory

Some mice will have software you can download which will allow you to change the
settings on the mouse such as: color of LEDs, CPI, and macros. Other mice will
have dedicated hardware buttons for some or all of these functions, if these are
important to you check the manufacturers website for software or see if it’s in
the feature list.